Re: GIT for pdiff generation
On Sun, 27 Mar 2011, Joerg Jaspert wrote:
> Right now the source contents of unstable has, unpacked, 220MB. (Packed
> gzip its 28MB, while the binary contents per have each have 18MB
That should not be a problem in any non-joke box. Unless you'll run it
in a memory-constrained vm or something.
> Lets add a safety margin: 350MB is a good guess for the largest.
> A packages file nearly doesnt count compared to them, unpacked its just
> some 34mb
I.e. something very easy to keep in RAM on a "server class" or "desktop
> > There is an alternative: git can rewrite the entire history
> > (invalidating all commit IDs from the start pointing up to all the
> > branch heads in the process). You can use that facility to drop old
> > commits. Given the indented use, where you don't seem to need the
> > commit ids to be constant across runs and you will rewrite the history
> > of the entire repo at once and drop everything that was not rewritten,
> > this is likely the less ugly way of doing what you want. Refer to git
> > filter-branch.
> Its the one and only thing I ever seen where "history rewrite" is
> actually something one wants to do.
> > Other than that, git loads entire objects to memory to manipulate them,
> > which AFAIK CAN cause problems in datasets with very large files (the
> > problem is not usually the size of the repository, but rather the size
> > of the largest object). You probably want to test your use case with
> > several worst-case files AND a large safety margin to ensure it won't
> > break on us anytime soon, using something to track git memory usage.
> Well, yes.
At the sizes you explained now (I thought it would deal with objects 7GB
in size, not 7GB worth of objects at most 0.5GB in size), it should not
be a problem in any box with a reasonable ammount of free RAM and vm
space (say, 1GB).
> Some NM:
> > FTBFS=Fails to Build from Start
> Err, yes? How do you start in the middle?
You screw up debian/rules clean, and try two builds in sequence ;-)
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